Claudio M Garcia-Herrera

University of Santiago, Chile | USACH · Departamento de Ingeniería Mecánica

This article focuses on agar biopolymer films that offer promise for developing biodegradable packaging, an important solution for reducing plastics pollution. At present there is a lack of data on the mechanical performance of agar biopolymer films using a simple plasticizer. This study takes a Design of Experiments approach to analyze how agar-gl...

In recent years, there has been an increasing interest of engineers and architects in the use of timber in the construction sector. This worldwide trend can be mainly attributed to the reduced environmental impact of building with timber, its high strength-to-weight ratio and its renewable material nature. Nevertheless, in spite of the advantages o...

Although EK4 drawing steel is nowadays widely used to manufacture a great variety of parts, it exhibits a marked normal and planar anisotropy that can make it difficult to control the process during its forming. In order to achieve an accurate description of the elastoplastic material response in sheet forming operations, this work presents a detai...

Environmental variation alters biological interactions and their ecological and evolutionary consequences. In coastal systems, trematode parasites affect their hosts by disrupting their life-history traits. However, the effects of parasitism could be variable and dependent on the prevailing environmental conditions where the host-parasite interacti...

High altitude hypoxia is a condition experienced by diverse populations worldwide. In addition, several jobs require working shifts where workers are exposed to repetitive cycles of hypobaric hypoxia and normobaric normoxia. Currently, few is known about the biomechanical cardiovascular responses of this condition. In the present study, we investig...

Nowadays, biomedical films containing drug carriers are preferred over conventional ones, since the protection of the injury and the therapy is joined within a single device. In the current work, we prepared polycaprolactone (PCL) composite films with β-cyclodextrin (βCD) or its epichlorohydrin crosslinked polymer (βCDP) as ibuprofen (Ibu) drug car...

Increased carbon dioxide levels (CO 2) in the atmosphere triggered a cascade of physical and chemical changes in the ocean surface. Marine organisms producing carbonate shells are regarded as vulnerable to these physical (warming), and chemical (acidification) changes occurring in the oceans. In the last decade, the aquaculture production of the bi...

Mollusks have developed a broad diversity of shelled structures to protect against challenges imposed by biological interactions(e.g., predation) and constraints (e.g., $$pCO_2$$ p C O 2 -induced ocean acidification and wave-forces). Although the study of shell biomechanical properties with nacreous microstructure has provided understanding about t...

The exposure to environmental variations in pH and temperature has proven impacts on benthic ectotherms calcifiers, as evidenced by tradeoffs between physiological processes. However, how these stressors affect structure and functionality of mollusk shells has received less attention. Episodic events of upwelling of deep cold and low pH waters are...

Biocompatible smart interfaces play a crucial role in biomedical or tissue engineering applications, where their ability to actively change their conformation or physico-chemical properties permits finely tuning their surface attributes. Polyelectrolytes, such as acrylic acid, are a particular type of smart polymers that present pH responsiveness....

Background Body composition (BC) influences respiratory system mechanics, provoking air flow limitation (AFL). The objective of this study was to determine the relationship of AFL in small- and medium-caliber airways with BC in young adults. Methods Eighty-three individuals were recruited (40 men and 43 women). To determine AFL, the following meas...

The present study involves experiments and modeling aimed at characterizing the passive structural mechanical behavior of the chronic hypoxic lamb thoracic aorta, whose gestation, birth and postnatal period were carried at high altitude (3600 masl). To this end, the mechanical response was studied via tensile and pressurization tests. The tensile a...

In order to reliably assess the rupture-risk of the aorta – along with the hazardousness index of cardiovascular diseases or other extreme conditions, and the effect of possible treatments – it is necessary to know the damage mechanisms that lead to it. In this work, the mechanical damage of hypoxic aortic tissue is characterized, numerically predi...

The nanoindentation‐induced mechanical deformation response is applied to identify the orthotropic elastic moduli using the Delafargue & Ulm method as well as to validate the asymmetric orthotropic CPB06 non‐linear plasticity model required in simulations of non‐uniform macroscopic mechanical response of the Ti–6Al–4V alloy. Scanning electron micro...

The need for new technologies more efficient and less expensive to remove heavy metals from aqueous environments has lead to the development of novel biosorption-based membranes, where the adsorbent agent has a biological origin. In this work we propose the use of the biopolymer from a highly invasive microalgae, Didymosphenia geminata or Didymo, a...

In this work, a novel numerical-experimental procedure is proposed, through the use of the Cardiac Simulation Test (CST), device that allows the exposure of the arterial tissue to in-vitro conditions, mimicking cardiac cycles generated by the heart. The main goal is to describe mechanical response of the arterial wall under physiological conditions...

ABSTRACT: In order to reliably assess the rupture-risk of the aorta-along with the hazardousness index of cardiovascular diseases or other extreme conditions, and the effect of possible treatments-it is necessary to know the damage mechanisms that lead to it. In this work, the mechanical damage of hypoxic aortic tissue is characterized, numerically...

RESUMEN Para evaluar de manera fidedigna el riesgo de ruptura de la aorta – junto a los índices de peligrosidad de enfermedades cardiovasculares u otras condiciones extremas y los efectos de posibles tratamientos – se requiere conocer los mecanismos de daño que conducen a ésta. En este trabajo, se caracteriza el daño mecánico del tejido aórtico en...

Efficiency of coin manufacturing is often limited by the service life of the stamping dies, whose degradation by wear results in decreasing the quality of the produced coin engraving. The aim of this work is to explore the ability of the combined application of experimental characterization and numerical simulation of the material elastoplastic for...

This article presents the mechanical responses of Pinus radiata wood that was impregnated with octadecane to obtain a shape-stabilized phase change material (PCM). PCMs are used as heat storage materials to reduce the temperature peaks and displace the thermal loads in an enclosed space. It is important to study the effect of PCMs on the mechanical...

This work presents an elastoplastic characterization of a rolled C11000-H2 99.90% pure copper sheet considering the orthotropic non-associated Hill-48 criterion together with a modified Voce hardening law. One of the main features of this material is the necking formation at small strains levels causing the early development of non-homogeneous stre...

In this study, we assessed the effects of Atrial Natriuretic Peptide (ANP) and Cinaciguat, as experimental medicines to treat neonatal lambs exposed to chronic hypoxic conditions. To compare the different treatments, the mechanical responses of aorta, carotid, and femoral arterial walls were analyzed by means of axial pre-stretch and ring-opening t...

Lung function evaluation through computerized tomography and 3D reconstruction of airways: A body mass index pilot study. Int. J. Morphol., 38(5):1223-1228, 2020. SUMMARY: Obesity is a worldwide epidemic that has become a risk factor for the development of respiratory problems, meaning it is necessary to generate models that assess lung function in...

Chronic hypoxia is a condition that increases the cardiovascular complications of newborns gestated and born at high altitude (HA), over 2,500 m above sea level (masl). A particularly complex pathology is pulmonary arterial hypertension of the neonate (PHN), which is increased at HA due to hypobaric hypoxia. Basic and clinical research have recogni...

Environmental variation may alter biological interactions and their ecological consequences. For instance, in marine ecosystems hosts and parasites are subject to environmental variability across latitudinal gradients, and their co-evolutionary dynamics may be the result of the interplay with local physical-chemical variables in seawater. Thus, ass...

Deformability and internal ordering are key features related to cell function, particularly critical for cells that routinely undergo large deformations, like T cells during extravasation and migration. In the measurement of cell deformability, a considerable variability is typically obtained, masking the identification of possible interrelationshi...

The incorporation of phase change materials (PCM) in construction components has become an alternative to reduce the effect of thermal loads in buildings with low thermal inertia. This study put together the effective heat storage capacity of an organic phase change material (O-PCM, octadecane) with the construction and production potential of Pinu...

3D printing has gained great popularity due to its main feature of manufacturing complex geometries. The building process by adding successive layers generates mechanical properties that depend on the printing parameters, where build orientation is one of the most relevant factors. Due to this, the characterization of the mechanical response of the...

This work presents an experimental and numerical analysis of the mechanical behavior of a fixed-end SAE 1045 steel cylindrical specimen during the torsion test. To this end, an iterative numerical-experimental methodology is firstly proposed to assess the material response in the tensile test using a large strain elastoplasticity-based model solved...

This work presents an experimental and numerical analysis of the mechanical behavior of a fixed-end SAE 1045 steel cylindrical specimen during the torsion test. To this end, an iterative numerical-experimental methodology is firstly proposed to assess the material response in the tensile test using a large strain elastoplasticity-based model solved...

Extensive periods of hypoxic cause adaptive changes that make it possible to respond to the demands imposed by the environment. However, there are cases where this exposure is intermittent, as is the case of workers in andean areas. The objective of this communication was to verify the morphological and mechanical effects on diaphragm and lungs of...

An amendment to this paper has been published and can be accessed via a link at the top of the paper

Design strategies for small diameter vascular grafts are converging toward native-inspired tissue engineered grafts. A new automated technology is presented that combines a dip-spinning methodology for depositioning concentric cell-laden hydrogel layers, with an adapted solution blow spinning (SBS) device for intercalated placement of aligned reinf...

In the present work, we have studied the laminar (200 ⩽ Re ⩽ 1200) three-dimensional flow of a water-based nanofluid in rectangular microchannels of constant wide cross section (283 μm) and three different heights (800 μm, 600 μm, and 400 μm). Moreover, we analyse the concentration of dispersed TiO2 nanoparticles (<6 nm) on the thermal and hydrauli...

Aim: Fetal growth restriction (FGR) is associated with endothelial dysfunction and cardiovascular diseases in adult subjects. Early vascular remodelling and epigenetic changes occurring on key endothelial genes might precede this altered vascular function. Further, it has been proposed that oxidative stress during development may determine some of...

CONEI, D.; DEL SOL, M.; MUÑOZ, R.; ESCOBAR, C. M.; SAAVEDRA, H.; HERRERA, E. A. & GARCÍA-HERRERA, C. M. Efectos morfológicos y mecánicos en ratas Sprague Dawley sometidas a ciclos de hipoxia. Int. J. Morphol., 37(3):908-911, 2019. RESUMEN: Periodos extensos de hipoxia provocan cambios adaptativos que permiten responder a las demandas impuestas por...

La presente investigación tiene por objetivo aplicar un enfoque Galerkin Discontinuo (DG) a la simulación numérica de sólidos hiperelásticos. Para validar numéricamente la implementación computacional del método Galerkin Disconti-nuo, se resuelven casos clásicos de elasticidad no-lineal que tienen solución exacta. Por último, se estudia la sensibil...

Fetal growth restriction (FGR) is a perinatal condition associated with a low birth weight that results mainly from maternal and placental constrains. Newborns affected by this condition are more likely to develop in the long term cardiovascular diseases whose origins would be in an altered vascular structure and function defined during fetal devel...

This work presents numerical simulations and an experimental validation of sheet laser forming processes using general scanning paths with different laser beam operating parameters (i.e., power, diameter, and scanning speed) in two specific graphite coated stainless steel blanks (i.e., with thicknesses of 0.3 mm and 0.6 mm for the AISI 302 and 304...

This work presents numerical simulations and experimental validation of sheet laser forming processes using a single-step straight path with different laser beam powers (four levels ranging from 30 W to 120 W) and scanning speeds (four levels ranging from 5 mm/s to 20 mm/s) in graphite-coated AISI 304 stainless steel 0.6-mm-thick sheets. The numeri...

Nanofluids are a type of composite material with a demonstrated potential for improving heat transfer processes present in industries such as computers, electronics, and automobile. However, they have a limitation, which is that the suspended nanoparticles tend to agglomerate and in that way decrease their thermophysical properties. The present wor...

More than 140 million people live and works (in a chronic or intermittent form) above 2500 m worldwide and 35 million live in the Andean Mountains. Furthermore, in Chile, it is estimated that 55,000 persons work in high altitude shifts, where stays at lowlands and interspersed with working stays at highlands. Acute exposure to high altitude has bee...

We present a conservative formulation for the frictional contact forces developed in the framework of an energy-consistent method. Bilateral constrains, that is, joints and rigid links, are imposed using the augmented Lagrange technique, provided that the constraints are exactly satisfied. We propose a formulation based on a penalty method to deal...

Addition of fibers to cement-based materials improve tensile and flexural strength, fracture toughness, abrasion resistance, delay cracking, and reduce crack widths. Natural fibers have recently become more popular in the construction materials community. This investigation addresses the characterization of a new animal fiber (pig hair), a massive...

A numerical and experimental analysis of the mechanical response of asphalt felt paper is presented. This material is widely used as a moisture barrier in buildings made of light materials. To ensure such function, it is necessary for this material not to be torn during its installation and operation and, for this reason, it is important to know it...

Aim: Fetal growth restriction (FGR) is associated with a variety of cardiometabolic diseases in adulthood which could involve remodeling processes of the vascular walls that could start in the fetal period. However, there is no consensus whether this remodeling affects in a similar way the whole vascular system. We aimed to determine the effects of...

Marfan syndrome (MFS) is a genetic disorder that affects connective tissue, impairing cardiovascular structures and function, such as heart valves and aorta. Thus, patients with Marfan disease have a higher risk of developing circulatory problems associated with mitral and aortic valves prolapse, manifested as dilated aorta and aortic aneurysm. How...

As in most countries, Chile exhibits a continuous growth of energy demand, although nowadays the country does not have enough conventional energy sources to supply it. For this reason, energy saving approaches in the residential sector have been encouraged. One of the solutions to improve the energy performance of the buildings is to decrease wasti...

This chapter presents an overview of recent works aimed at characterizing the mechanical behaviour of the human aorta via experiments, modeling and simulation. The application of these techniques are in particular detailed in the analysis of the following cases: ascending aorta, aortic arch and thoracic descending aorta under in-vitro and in-vivo c...

This work presents experiments, modelling and numerical simulation aimed at describing the mechanical response of human ascending aortas in the ring opening test. The objective is to quantify, from the opening angles measured in the test, the residual stress distribution along the artery wall and, afterwards, how this stress pattern changes when th...

This work presents the modeling and simulation of the mechanical response of a Dacron graft in the pressurization test and its clinical application in the analysis of an end-to-end anastomosis. Both problems are studied via an anisotropic constitutive model that was calibrated by means of previously reported uniaxial tensile tests. First, the simul...